Hydrogen powered electric vehicles have tremendous potential. Unfortunately, producing it requires as much energy as you get out of it, meaning a huge investment in dedicated alternative energy power plants to produce it. Getting it to the gas stations will require another huge investment in new distribution and delivery infrastructure. And the logistics of storing it in your vehicle, either at near absolute zero in liquid form or under tremendously high pressures in a special tank, don't look too good or safe either right now.
Since our economy is built on the concept of generally doing things as cheaply as possible, this may never happen in our lifetimes. However, if we could pull this off in the next 10 - 20 years I do believe that stopping the shipment of all of our dollars overseas to quench are insatiable oil thirst will solve nearly every single problem our country has!
THINK ABOUT IT!

No doubt its going to take considerably effort to develop a mass market hydrogen system BUUUUUUUUUUTTTTTTTT.....

Today we drill oil from miles below the ocean, load it into massive tankers to ship it across the world, then refine it and then put it into pipelines to be delivered by trucks. Some really impressive logistics in its own right.

Right now running hydrogen costs about 2-3x as much as fuel (when including the cost of the car) and its in its infancy vs a very mature system. It will change, and I believe change more quickly than most imagine.